Swaks
Net-SSLeay: Perl bindings for OpenSSL and LibreSSL
Expect-lua for Windows ( A text-terminal automation tool similar to expect(1) using Lua )
An ad-hoc disposable temporary mail server. Create and use ad hoc disposable mailboxes for testing or any other purpose.
Create custom SMTP servers on the fly
dsmtpd is a small SMTP server for debugging and the developers.
A fast, highly extensible, and event driven SMTP server
Maildroid is a small robust android library for sending emails using SMTP server
mailproxy is a simple SMTP proxy. It receives emails through an unencrypted, unauthenticated SMTP interface and retransmits them through a remote SMTP server that requires modern features such as e…
Disposable webmail server (similar to Mailinator) with built in SMTP, POP3, RESTful servers; no DB required.
Exim Mail Transport Agent - source, testsuite and documentation
A simple SMTP Server for Testing purposes. Emails are stored in an in-memory database and rendered in a Web UI
JSON Meta Application Protocol Specification (JMAP)